A tennis swing differs from player to player. A swing is influenced by the specifications of the tennis racket. For example, attempting to hit a ball at high speed with a racket that has a low coefficient of restitution will cause the player to strain. On the other hand, attempting to control the velocity when hitting a ball with a racket whose coefficient of restitution is too high will cause looseness in the player's hand. It is important to have a match between the player and the racket. In order to do that, appropriate swing analysis is necessary, and it can contribute to an improvement in the player's skill. Appropriate swing analysis can contribute to research and development for tennis racket, which will contribute to sales of tennis racket.
Various techniques have been considered for such swing analysis, and as one example, Patent Document 1 discloses an apparatus for analyzing racket behavior based on images obtained by filming a swing with three high-speed cameras.
Also, Patent Document 2 discloses a swing speed measuring method, and in this method, a magnet is attached to the tip of a racket. The swing speed can then be calculated by detecting the passage of this magnet with a sensor.
Furthermore, Patent Document 3 discloses a method for analyzing a swing using a triaxial acceleration sensor and a triaxial gyroscope.